The present invention relates to a display apparatus, for enlargedly projecting an image or picture displayed on a display device, onto a screen through a projection lens, and it relates, in particular, to a display apparatus preventing dusts from entering into an inside of the display apparatus.
In the display apparatus, projecting an image or picture displayed on a display device(s) of liquid crystal, etc., on a screen from a rear side thereof by means of a projection lens, optical parts, such as, the display device(s) and polarizing plate (s), which are provided around them, generates heats due to light incident thereupon. It is necessary to cool down those optical parts, from a viewpoint of a long lifetime, etc., and it is general to provide a fan or the like, so as to obtain air-cooling thereof. Also, those optical parts, since the performances thereof are deteriorated when dusts attach thereon, there is necessity of suppressing the dusts from entering into an air duct for a cooling air.
With the display apparatus of the conventional arts, suppressing is made on permeation of the dusts, by sucking an air inside an upper cabinet, which is sealed with a screen and a cabinet, thereby to cool down the display devices of an optical unit and the optical parts provided around there, which are installed within a lower cabinet, due to that air, and discharging the air after cooling into the upper cabinet, again, i.e., like so-called an inner air circulation. The cooling structure of such is already disclosed in Japanese Patent Laying-Open No. 2004-294781 (2004), for example.